On some copper(I) perthiocarboxylates and their reactions with tertiary phosphines. Crystal structure of tetra(p-tolyldithiocarboxylato)tetracopper(I), [CuS2C-p-tolyl]4, and of [bis(triphenylphosphine)(p-tolyldithiocarboxylato)copper(I)] triphenylphosphine sulfide, [CuS2C-p-tolyl(PPh3)2]·PPh3S